Noise Dosimeter with Adaptive Sampling for Impulse Noise
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Solution Overview
Problem
Current noise dosimeters fail to accurately measure noise exposure, especially in environments with impulsive sounds, due to limitations in dynamic range, frequency range, and placement, which can lead to incomplete or inaccurate exposure measurements.
Innovation Solution
A portable system with high sampling rates and broad spectral capabilities, including a combination of microphones and an analog-to-digital converter, capable of recording impulse noise with rapid rise times and high peak amplitudes, while being small, lightweight, and low-power, allowing for continuous data collection in rugged environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If typical commercial noise dosimeters are used, then device simplicity and low cost are maintained, but measurement precision and dynamic range are insufficient for impulsive sounds
Solution Approach 1:
The system divides noise measurement into multiple frequency bands (e.g., 1/3 octave bands) and processes each band separately with dedicated filtering and analysis, enabling precise measurement of complex impulsive sounds while maintaining manageable system complexity through modular architecture
Solution Approach 2:
The dosimeter system performs multiple functions including real-time noise level monitoring, impulse noise detection, spectral analysis across multiple frequency bands, and dosimetry calculation, all within a single integrated device that replaces multiple specialized instruments
2Measurement precision
If high sampling rates and broad spectral capabilities are implemented, then measurement precision for impulsive sounds is improved, but device size and power consumption increase
Solution Approach 1:
The system dynamically adjusts sampling rate and frequency analysis parameters based on the detected noise characteristics - using high sampling rates (e.g., 48 kHz or higher) only when impulsive sounds are detected, while operating at lower rates for continuous noise, thereby achieving high measurement precision without constant high-power consumption and reduced device weight
3Measurement precision
If microphones are placed close to the ear for accurate personal exposure measurement, then measurement precision is improved, but susceptibility to physical damage and environmental factors increases
Solution Approach 1:
The microphone element is protected by a acoustically transparent membrane or grille that filters out physical debris, moisture, and extreme pressure changes before they can damage the sensitive microphone, while maintaining accurate noise measurement capability - providing beforehand protection against environmental damage
4Device complexity
If equal-energy hypothesis is used for dosimetry, then calculation simplicity is maintained, but measurement precision for impulsive sounds deteriorates
Solution Approach 1:
The dosimetry system dynamically selects between different calculation methods - using the simplified equal-energy hypothesis for continuous noise conditions, but switching to impulse-specific metrics (such as peak pressure, rise time, and impulse duration) when impulsive sounds are detected, thereby maintaining calculation simplicity while improving dosage accuracy for impulsive noise
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise estimation of sound exposure and development of advanced hearing protection strategies by capturing detailed noise histories, including impulsive sounds, in various challenging environments.
Implementation Method 1
a first microphone, which may be worn on an article of clothing, a hat, a helmet, or a bag, produces a first analog signal representative of sound
Data Source
AI summary
Systems, apparatus, and methods for collecting, interpreting, and utilizing noise exposure data may include sensors to obtain an analog signal representative of impulse noise sound pressure and an analog signal representative of continuous noise sound pressure. At least one ADC may generate digital signals by sampling the analog signals at rates equal to or greater than twice the reciprocal of a minimum impulse noise rise time. Accelerometers may obtain data in close proximity to and remote from the sensors. At least one processor may include a first combining node to combine the digital signals to represent both the continuous noise and the impulse noise, a shock-artifact detection filter to identify a time frame including a shock artifact based on the accelerometry data, a frequency filter to generate a background-removed audio signal, an adaptive filter to estimate the shock artifact, and a second combining node to produce a shock-artifact-free audio signal.